Biblical preaching and discipleship
You cannot make a disciple of Jesus Christ without biblical preaching. This is because disciples, followers of Jesus are hearers and doers of the Word (Mt 7:24, Jms 1:22). And you cannot be a doer of the Word if you do not understand the Word. So in biblical preaching, the preacher must use the Word of God to communicate the truth about God, grace and godliness. The preacher's message has as its aim the conversion sinners and the edification of believers - to transform the hearer by the renewing of the mind (Rom 12:1-2) That message must be heard and received for the creating and making of disciples.
It is also important that the message is received. We cannot receive the message without hearing it preached. (Rom 10:14-17) Listening to the Bible preached is a necessary part of discipleship. One of the reasons for that is the Bible itself is God Himself preaching to us. It's no wonder that in the Bible, God specifically instructs preachers to emphasize the reading and preaching of the Bible in their ministry. Paul says to Timothy "Give your attention to public reading, exhortation, and teaching (1 Tim 4:13). With the utmost solemnity he exhorts Timothy again. " I solemnly charge you before God and Christ Jesus, who is going to judge the living and the dead and because of his appearing and His kingdom: Proclaim the message; persist in it, whether convenient or not; rebuke, correct, and encourage with great patience and teaching (2 Tim 4:1-2)
What Paul is saying here is especially to preachers, is neither unprecedented nor unique to him. Jesus said it before him - and so did Ezra! (Ezra 7:10) Think of Jesus' words in his prayer for believers in John 17, when he prayed "Sanctify them by the truth; Your Word is truth (Jn 17:17). Jesus is indicating, among other things that being taught the truth of God's Word is essential and indispensable to discipleship. This comes out clearly in the Great Commission.
In Matthew 28:19-20 Jesus says: "Go therefore, and make disciples of all nations, baptizing them in the name of the Father, and of the Son and the Holy Spirit, teaching them to observe everything I have commanded you." Did you catch that? Jesus just told you how to make a disciple (baptizing and teaching). And the emphasizes not just on teaching the minimal basics but "all I have commanded you" or to put it in another biblical phrase, "the whole plan of God" (Acts 20:27). So the teaching Jesus commands aims for obedience, for life transformation, "teaching them to observe everything I have commanded you." That's why Paul will explain that the goal of his preaching ministry this way: "Now the goal of our instruction is love that is from a pure heart, a good conscience and sincere faith" (1 Tim 1:5). Preaching aims to produce loving disciples - hearers and doers of the Word.
Since faith comes from hearing (Rom 10:14, 17) The Bible is profitable and sufficient to equip the believer for every good work (2 Tm 3:16-17) and God Himself has modeled and appointed in the Bible that preaching the Bible is His prime means of grace in the gathering and growing of believers, then the Bible will be the substance of the rule for faithful preaching.